Ski safety binding element

ABSTRACT

The toe or heel holder of a safety binding is pivotally mounted on a stub shaft, and held in its angular operating position by a spring-loaded, spherical detent guided in a bore of the holder radially relative to the shaft axis toward one of four equiangularly offset notches in the shaft which differ in their depth. The shaft is attached to the top surface of the ski by a square mounting plate and four screws at the corners of the plate so that the detent engages different notches in the shaft, and therefore resists deflection of the holder from its operating position with different force depending on the orientation of the mounting plate on the ski surface.

United States Patent [191 Sittmann Jan. 1, 1974 [5 SKI SAFETY BINDING ELEMENT 3,473,816 10/1969 Unger 280/1 1.35 T [75] Inventor: Brigette Sittmann, Stuttgart,

Germany Primary Examiner-Robert R. Song 1 3 Att0rneyl(urt Kelman et al. [73] Ass1gnee: Verermgte Baubeschlagfabriken Gretsch & Co. GmbH, Leonberg, Germany [57] ABSTRACT [22] Filed; N 2, 1972 The toe or heel holder of a safety binding is pivotally mounted on a stub shaft, and held in its angular oper- [zl] Appl' 303032 ating position by a spring-loaded, spherical detent guided in a bore of the holder radially relative to the [30] Foreign Application Priority Data shaft axis toward one of four equiangularly offset Nov. 3, 1971 Germany P 21 54 639.4 notches in the shaft which differ in their depth The shaft is attached to the top surface of the ski by a 52 us. c1 2s0/11.35 T Square mounting Plate and four Screws at the corners 511 1111.01. A63c 9/00 0f the plate so that the deter" engages different 58 Field of Search 280/11.35 T notches in the Shah, and therefore resists deflection 0f the holder from its operating position with different [56] References Cited force depending on the orientation of the mounting UNITED STATES PATENTS plate on the ski surface.

3,572,739 3/1971 Erlebach 280/11.35 T 7 Claims, 1 Drawing Figure SK! SAFETY BINDING ELEMENT This invention relates to ski: safety bindings, and particularly to a shoe holder for a safety binding which releases the shoe, and thereby the skiers leg from the ski under transverse or twisting stresses which may endanger the leg.

Many known safety bindings are equipped with toe holders and/or heel holders, hereinafter jointly referred to as shoe holders, which pivot on a shaft about an axis perpendicular to the top surface of the ski toward and away from an operating position in which they hold a skiers shoe or boot, and. are normally held in the angular operating position by a spring-loaded detent.

The known detents are usually of circular cross section, either spherical or cylindrical, and are biased into engagement with a notch in the shaft of the shoe holder by a helical compression spring seated on the holder. The stress of the spring determines at least in part the critical force to which the holder yields to release the skiers leg. The force with which the known detents impede angular movement of the shoe holder may be adjusted by means of a threaded seat or abutment for the spring which may be moved toward or away from the shaft axis. The known abutment may move on its threads when the binding is subjected to impact or vibration inherent in normal skiing, and a person not possessed of the necessary experience may set the abutment to an unsafe positon. Proper functioning of the binding critically depends on a proper setting of the release force.

It is a primary object of this invention to provide a safety binding element of the type described in which spontaneous changes in the setting of the releasing force and changes in the setting by unskilled persons are either prevented or at least limited to minor adjustment insufficient seriously to endanger the limbs of the skier.

With this object and others in view, the invention provides the shaft for the shoe holder of a safety binding element of the type described with at least two radial recesses or notches which are angularly offset about the axis of the shaft, and with a fastening arrangement which permits the shaft to be fastened to the longitudinal top surface of a ski in each of at least two positions offset about the shaft axis by an angle substantially equal to the angular offset of the recesses. In these positions, respective recesses are located in a predetermined plane which includes the axis of the shaft.

A spring-loaded detent is guided in or on the shoe holder in the afore-mentioned plane in the operating position of the holder toward and away from abutting engagement with the shaft in the recess which is located in that plane, and the two or more recesses differ in their configuration in such a manner that the detent impedes angular movement of the shoe holder away from its operating position with greater force when engaging one recess than when engaging the other.

Other features, additional objects, and many of the attendant advantages of this invention will readily be appreciated as the same becomes better understood by reference to the following detailed description of a preferred embodiment when considered in connection with the appended drawing in which the sole FIGURE illustrates a portion of a ski having a safety binding element of the invention attached thereto, the element being shown partlyin top plan view, and partly in plan section.

A stub shaft 1 of generally cylindrical shape pivotally supports the toe holder 2 of a safety ski binding. Four radial notches 3, 4, 5, 6 are formed in the cylindrical surface of the shaft 1 in equiangularly spaced relationship in a common plane transverse to the shaft axis. The planar walls of the notches converge toward the shaft axis at equal angles, but differ in depth, the notch 3 being deepest and the notch 6 shallowest.

A plate 7 integral with or fixedly fastened to the shaft 1 extends in a plane radial relative to the shaft axis at one end of the shaft 1. The plate 7 has the shape of a square with rounded edges. The fillister heads of screws 8, 9, l0, 11 project above the top surface of the plate 7, and their shanks, obscured in the drawing, freely pass through respective openings in the four comers of the plate 7 and fixedly fasten the plate together with the shaft 1 to the top surface of a ski 17, only partly seen in the drawing. The four openings in the plate 7 are equiangularly spaced about the axis of the shaft 1 and equidistant from the same within ordinary manufacturing tolerances.

A bore 12 in the toe holder 2, radial to the axis of the shaft 1, and parallel to the direction of elongation of the ski 17, encloses a helical compression spring 13 interposed between a steel ball 14 and a threaded plug 15 at the radially outer end of the bore 12. This end is threaded over only a few turns more than the length of the plug 15 so as to permit the plug to be moved toward the shaft 1 a short distance by means of a coin or screw driver inserted in a diametrical notch 18 in the outer face of the plug. Outward movement of the plug 15 from its illustrated position in the bore 12 is prevented by a centrally apertured screw cap 19.

The shaft 1 is received on a blind bore of the toe holder 12 so that the shaft 1 is completely obscured in the assembled condition of the safety binding element. A spacer ring 20 on the shaft 1 holds the flat bottom face of the toe holder 2 sufficiently above the top face of the plate 7 to prevent the heads of the screws 8, 9, l0, 11 from touching the toe holder. A stop 16 projects downward from the toe holder 2 toward the plate 7 abuttingly to engage the projecting heads of the screws 10, 11 when the toe holder 2 is turned about 45 in either direction from the illustrated operating position in which the bore 12 is located in a common plane including the axis of the shaft 1 with the notch 3, and the walls of the bore guide the ball 14 toward and away from the illustrated position of abutting, generally radial engagement with the shaft 1 in the notch 3.

The ball 14 serves as a detent which impedes angular movement of the toe holder 2 away from the operating position with a force determined in part by the stress in the spring 13 which is at its minimum when the ball 14 is received in the relatively wide and deep notch 3, and the plug 15 abuts against the screw cap 19. The effective length of the spring 13 may be reduced, and the stress in the spring correspondingly increased by turning the plug 15 over the available short distance of the threads in the bore 12, somewhat smaller than the difference in effective depth of the notches 3 and 4.

For a greater change in the force required for turning the toe holder, it is necessary to withdraw the accessible screws 8, 9 from the ski 17, turn the toe holder 2 on the shaft 1 to expose the screws 10, 11, release the latter screws, and thereby the plate 7 from the ski, thereafter turn the toe holder 2 on the shaft-l until the ball 14 engages one of thenotches 4, 5, or 6, as may be desired, and ultimately again insert the screws 8, 9, 10, l 1 into the threaded bores of the ski 17 which mate the openings of the plate 7 in four different positions of the plate. lf the ball 14 engages the notch 6, for example, rotation of the toe holder 2 is limited by abutting engagement of the stop 16 with the screws 8, 11.

While the invention has been described with reference to a toe holder, heel holders closely similar in structure and function are commonly used in this art for cooperation with toe holders of the same or different construction, and the invention is not limited to a specific longitudinal end of a ski shoe or boot which normally engages the concavely arcuate face of the holder 2 diametrically opposite the bore 12 in the appended drawing.

lf so desired, a cylindrical detent, known in itself, may replace the illustrated spherical detent 14, and the notches 3-6 may be changed to a shape suitable for accomodating the modified detent. The notches have been shown to be of similar shape, and to differ only in their dimensions. However, other variations in their configuration may be resorted to in order to vary the force with which the detent 1 4 impedes angular movement of the shoe holder 2 from its illustrated position. The distance between the engaged detent and the axis of the shaft may thus be varied not only by varying the depth of the several notches, but also by varying their apex angles, if they are all of similar shape, or by mak ing them of different respective shapes.

It is normally most convenient to make the bore 12 and the plane through the axis of the shaft 1 in which the bore extends in the operating position of the shoe holder parallel to the direction of ski elongation, but different orientations ofthe bore and of the plane may be chosen under special conditions. The bore 12 thus may be transverse to the elongation of the ski, and it need not be parallel to the top face of the ski, but may be obliquely inclined relative to the axis of the shaft 1.

Four notches 3, 4, 5, 6 and four fastening screws 8, 9, l0, 1 l have been found satisfactory and convenient. However, the number of the notches or recesses may be decreased to not fewer than two without loss of all the advantages of this invention, and increased to five, six, seven, or even eight without unduly weakening the ski 17. Thus, the notches 4 and 6 may be omitted from the illustrated embodiment while the number of screws remains unchanged. With more than two notches, the number of screws may be increased to any integral multiple of the number of notches, and their angular spacing correspondingly reduced to an integral fraction of the angular spacing of the notches.

Other modifications and variations of the illustrated example of the invention will readily suggest themselves to those skilled in the art, and it should be understood, therefore, that this invention, within the scope of the appended claims, may be practised otherwise than as specifically described and illustrated.

What is claimed is:

1. A. safety binding element for a ski comprising, in combination:

a. a shaft member having an axis,

1. the surface of said shaft member being formed with at least two radial recesses angularly offset about said axis;

b. fastening means for fastening said member on the longitudinal top surface of a ski in each of at least two positions offset about said axis by an angle substantially equal to the angular offset of said recesses,

l. in said positions, respective ones of said recesses being located in a predetermined plane including said axis;

c. a shoe holder member mounted on said shaft member for angular movement relative to said shaft member about said axis toward and away from an operating position in fixed angular relationship to said top surface; and

d. detent means for releasably impeding movement of said shoe holder member away from said operating position, said detent means including 1. a detent member,

2. guide means on said shoe holder member for guiding said detent member in said predetermined plane toward and away from a position of abutting engagement with said shaft member in the recess located in said plane, and

3. yieldably resilient means interposed between said detent member and said shoe holder member for biasing said detent member into said position of abutting engagement, said recesses differing in configuration in such a manner that said detent member impedes said angular movement of said shoe holder member with greater force when engaging said shaft member in one of said recesses than when engaging said shaft member in the other recess.

2. An element as set forth in claim 1, wherein said fastening means include a plate member fixedly fastened to said shaft member and radial to said axis, said plate member being formed with two apertures therethrough in the direction of said axis, said apertures being spaced from said axis and angularly offset relative to said axis by said angle.

3. An element as set forth in claim 1, wherein said shoe holder member is formed with a bore extending in said plane in said operating position of the shoe holder member, the walls of said shoe holder member in said bore constituting said guide means, said yieldably resilient means including a compression spring received in said bore.

4. An element as set forth in claim 3, further comprising an abutment member, said spring being interposed between said abutment member and said detent member, and adjusting means for shifting said abutment member toward and away from said axis a distance smaller than the difference between the spacings of said detent member from said axis when said detent member engages said shaft member in said recesses respectively.

5. An element as set forth in claim 1, wherein said shaft member is formed with four of said radial recesses equiangularly spaced about said axis, and said fastening means include a plate member fixedly fastened to said shaft member and radial to said axis, said plate member being formed with four apertures therethrough in the direction of said axis, said apertures being substantially equidistant from said axis and substantially equiangularly spaced about said axis.

6. An element as set forth in claim 1, further comprising abutment means limiting angular movement of said shoe holder member away from said operating position to an angle smaller than said angular offset of said recesses.

7. An element as set forth in claim 1, wherein said detent member is nearer said axis when engaging said shaft member in one of said recesses than when engaging said shaft member in the other recess. 

1. A safety binding element for a ski comprising, in combination: a. a shaft member having an axis,
 1. the surface of said shaft member being formed with at least two radial recesses angularly offset about said axis; b. fastening means for fastening said member on the longitudinal top surface of a ski in each of at least two positions offset about said axis by an angle substantially equal to the angular offset of said recesses,
 1. in said positions, respective ones of said recesses being located in a predetermined plane including said axis; c. a shoe holder member mounted on said shaft member for angular movement relative to said shaft member about said axis toward and away from an operating position in fixed angular relationship to said top surface; and d. detent means for releasably impeding movement of said shoe holder member away from said operating position, said detent means including
 1. a detent member,
 2. guide means on said shoe holder member for guiding said detent member in said predetermined plane toward and away from a position of abutting engagement with said shaft member in the recess located in said plane, and
 3. yieldably resilient means interposed between said detent member and said shoe holder member for biasing said detent member into said position of abutting engagement, said recesses differing in configuration in such a manner that said detent member impedes said angular movement of said shoe holder member with greater force when engaging said shaft member in one of said recesses than when engaging said shaft member in the other recess.
 2. An element as set forth in claim 1, wherein said fastening means include a plate member fixedly fastened to said shaft member and radial to said axis, said plate member being formed with two apertures therethrough in the direction of said axis, said apertures being spaced from said axis and angularly offset relative to said axis by said angle.
 2. guide means on said shoe holder member for guiding said detent member in said predetermined plane toward and away from a position of abutting engagement with said shaft member in the recess located in said plane, and
 3. An element as set forth in claim 1, wherein said shoe holder member is formed with a bore extending in said plane in said operating position of the shoe holder member, the walls of said shoe holder member in said bore constituting said guide means, said yieldably resilient means including a compression spring received in said bore.
 3. yieldably resilient means interposed between said detent member and said shoe holder member for biasing said detent member into said position of abutting engagement, said recesses differing in configuration in such a manner that said detent member impedes said angular movement of said shoe holder member with greater force when engaging said shaft member in one of said recesses than when engaging said shaft member in the other recess.
 4. An element as set forth in claim 3, further comprising an abutment member, said spring being interposed between said abutment member and said detent member, and adjusting means for shifting said abutment member toward and away from said axis a distance smaller than the difference between the spacings of said detent member from said axis when said detent member engages said shaft member in said recesses respectively.
 5. An element as set forth in claim 1, wherein said shaft member is formed with four of said radial recesses equiangularly spaced about said axis, and said fastening means include a plate member fixedly fastened to said shaft member and radial to said axis, said plate member being formed with four apertures therethrough in the direction of said axis, said apertures being substantially equidistant from said axis and substantially equiangularly spaced about said axis.
 6. An element as set forth in claim 1, further comprising abutment means limiting angular movement of said shoe holder member away from said operating position to an angle smaller than said angular offset of said recesses.
 7. An element as set forth in claim 1, wherein said detent member is nearer said axis when engaging said shaft member in one of said recesses than when engaging said shaft member in the other recess. 